Walls of kindness: The viral trend keeping Iran's homeless warm

(CNN)Looking for something to restore your faith in humanity? This might just do the trick.

As Iran endures a cold winter, locals have devised an innovative scheme to help the homeless keep warm.

Spontaneous "walls of kindness," on which people can donate unwanted clothing, have popped up around the country.

The message is simple: "If you don't need it, leave it. If you need it, take it" -- next to several empty hooks and hangers.

According to government officials, there are 15,000 homeless people in Iran. Of these, one third are women. However, unofficial estimates put this figure much higher. Last year, Tehran municipality's Welfare Organization estimated that there are more than that number on the capital's streets alone.

The Iranian economy has been recovering since 2014, after suffering two years of recession. However, the unemployment rate remains high at 11.4%, according to the World Bank.

Much of the scheme's success stems from its visibility on social media platforms, where citizens have shared images using #WallOfKindness.

kindness wall 😊 If you don't need it put it here if you need it take it. My city of Esfahan - #IRAN . pic.twitter.com/477mCwYvbh
— parse marandi (@Parse_ir) December 14, 2015

Coats, trousers, hats and jumpers soon appeared, as passers-by sporadically left items behind. Those without warm clothes -- including the homeless population -- are encouraged to collect and keep donated items left behind.

The first "wall of kindness" is believed to have been erected in the city of Mashhad, northeast Iran, according to the BBC. Since then, replicas have sprung up in other cities, including Shiraz, Sirjan and Ilam.

"Have you heard of the wall of kindness?" asked a popular Iranian comedian on Facebook.

"If your city doesn't have one, getting one going is very easy. All you need is a suitable wall, some paint and clothes hooks. And then just spread the word."